Topic Contents

Luteinizing Hormone

Test Overview

A luteinizing hormone test measures the
amount of luteinizing
hormone (LH) in a sample of blood or urine. LH is
produced by the
pituitary gland.

In women, LH helps regulate the
menstrual cycle and egg production (ovulation). The level of LH in a woman's body varies
with the phase of the menstrual cycle. It increases rapidly just before
ovulation occurs, about midway through the cycle (day 14 of a 28-day cycle).
This is called an LH surge. Luteinizing hormone and
follicle-stimulating hormone levels rise and fall
together during the monthly menstrual cycle.

In men, LH stimulates
the production of
testosterone, which plays a role in sperm
production.

Why It Is Done

A luteinizing hormone (LH) test may be
done to:

Help find the cause for a couple's inability to
become pregnant (infertility). LH testing is commonly used to help evaluate:

A woman's egg supply (ovarian reserve).

A man's sperm count.

Help evaluate menstrual problems, such as
irregular or absent menstrual periods (amenorrhea). This can help determine if
the woman has gone through
menopause.

Determine if a child is going
through early
puberty (also called precocious puberty). Puberty is
early when it starts in girls younger than age 9 and in boys younger than age
10.

Determine why sexual features or organs are not developing when
they should (delayed puberty).

Determine (usually with a urine
sample) when a woman is ovulating. Home urine tests for ovulation are
available.

Monitor a woman's response to medicines given to
stimulate ovulation.

How To Prepare

Many medicines, such as cimetidine,
clomiphene, digitalis, and levodopa, can change your results. You may be asked
to stop taking medicines (including birth control pills) that contain
estrogen or
progesterone or both for up to 4 weeks before having a
luteinizing hormone (LH) test. Make sure your doctor has a complete list of all
the prescription and over-the-counter medicines you are taking, including herbs
and natural substances.

Tell your doctor if you have had a test
that used a radioactive substance (tracer) within the last 7 days. Recent tests
(such as a thyroid scan or bone scan) using a radioactive tracer can interfere
with LH test results.

Let your doctor know the first day of your
last menstrual period. If your bleeding pattern is light or begins with
spotting, the first day is the day of heaviest bleeding.

Talk to
your doctor about any concerns you have regarding the need for the test, its
risks, how it will be done, or what the results will mean. To help you
understand the importance of this test, fill out the
medical test information form(What is a PDF document?).

How It Is Done

Blood test

The health professional drawing blood
will:

Wrap an elastic band around your upper arm to
stop the flow of blood. This makes the veins below the band larger so it is
easier to put a needle into the vein.

Clean the needle site with
alcohol.

Put the needle into the vein. More than one needle stick
may be needed.

Attach a tube to the needle to fill it with
blood.

Remove the band from your arm when enough blood is
collected.

Apply a gauze pad or cotton ball over the needle site as
the needle is removed.

Apply pressure to the site and then a
bandage.

For women, more than one blood sample may be needed to
get an accurate indication of luteinizing hormone (LH) levels. Several blood
samples may be taken in one day, or one sample may be taken each day for
several days in a row.

Urine test for ovulation

To determine if you are
ovulating, a sample of your first urine of the morning is usually tested. It is
important to follow the package directions exactly if you are doing home
ovulation testing on a urine sample.

Place the collection container into the
stream of urine and collect approximately
4 Tbsp (60 mL) of
urine.

Do not touch the rim of the container to your genital area,
and do not get toilet paper, pubic hair, stool (feces), menstrual blood, or
other foreign matter in the urine sample.

Finish urinating into the
toilet.

You may also be given a plastic test strip to hold in the
urine stream. The test strip has a color indicator on it that can detect
luteinizing hormone (LH).

How It Feels

Blood test

You may feel nothing at all from the
needle puncture, or you may feel a brief sting or pinch as the needle goes
through the skin. Some people feel a stinging pain while the needle is in the
vein. But many people do not feel any pain (or have only minor discomfort) once
the needle is positioned in the vein.

Urine test

Collecting a urine sample does not
normally cause any discomfort.

Risks

Blood test

You may develop a small bruise at the
puncture site. You can reduce the risk of bruising by keeping pressure on the
site for several minutes after the needle is withdrawn.

In rare
cases, the vein may become inflamed after the blood sample is taken. This
condition is called phlebitis and is usually treated with a warm compress
applied several times daily.

Continued bleeding can be a problem
for people who have bleeding disorders. Aspirin, warfarin (Coumadin), and other
blood-thinning medicines can also make bleeding more likely. If you have
bleeding or clotting problems, or if you take blood-thinning medicine, tell
your doctor before your blood is drawn.

Urine test

There are no risks linked with
collecting a urine sample.

Results

A luteinizing hormone test measures the
amount of luteinizing
hormone (LH) in a sample of blood or urine.

LH levels depend on a person's age and stage of sexual development, and,
in a woman, on the phase of her
menstrual cycle. The urine test to determine whether a
woman is ovulating detects only the presence (positive result) or absence
(negative result) of LH.

Normal

The normal values listed here—called a reference range—are just a guide. These ranges vary from lab to lab, and your lab may have a different range for what's normal. Your lab report should contain the range your lab uses. Also, your doctor will evaluate your results based on your health and other factors. This means that a value that falls outside the normal values listed here may still be normal for you or your lab. Ask your doctor for normal values of your luteinizing hormone
test.

Luteinizing hormone in urine

Most home urine tests to predict ovulation determine only
the presence of LH (called qualitative testing) and not the specific level or
quantity. Home urine test results are either "positive" (LH is present) or
"negative" (LH is not present).

Many conditions can change LH levels. Your doctor will
discuss any significant abnormal results with you in relation to your symptoms
and past health.

What To Think About

If you are taking a medicine that contains
testosterone, estrogen, or progesterone (such as birth control pills), ask your
doctor whether you should stop taking it for several days before having a
luteinizing hormone (LH) test.

You can buy home ovulation kits at
a drugstore to help identify the most fertile days of a woman's menstrual
cycle. The kits test for LH in urine with a dipstick or test strip. Other home
ovulation tests that measure the amount of LH in urine and display the results
on a small computerized monitor also are available.

Other tests for
ovulation include measuring basal body temperature, testing the progesterone
level after ovulation in the menstrual cycle, and noting changes in cervical
mucus. To learn more, see the topic
Fertility Awareness.

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